(a) Field of the Invention
The present invention relates to a conditional access system (CAS), and in particular, it relates to a digital broadcast transmitting system and method for providing a conditional access to a user by each broadcasting service provider when there are plural broadcasting service providers, and a digital broadcasting receiving terminal and a method thereof in a single or multiple frequency network.
(b) Description of the Related Art
Digital broadcasting has characteristics of providing multiple channels, high quality, and multiple functions. In particular, development of multiplexing techniques has enabled concurrent combination of images, speech, and data irrespective of contents, size, and transmission thereof, and has formed a return channel through a modem to allow interactive services. Accordingly, digital data broadcasting has overcome the problems of conventional analog broadcasting and has provided multimedia services with high added value to viewers.
Particularly, the terrestrial digital video broadcasting (i.e., Digital Video Broadcasting-Terrestrial: DVB-T) and the DVB-T based digital mobile broadcasting (i.e., Digital Video Broadcasting-Handheld: DVB-H) among digital broadcasting standards are European digital TV broadcasting for transmitting video images and sound data to receivers through broadcasting wireless communication signals.
When no mutual stability system is guaranteed between the transmitter and the receiver in the above-noted digital broadcasting, the commercial broadcasting system cannot exist. Broadcasting service providers quality broadcasting services to subscribers by activating multiple channels and professional channels instead of the conventional services that depend on the advertisement incomes, provide charged broadcasting services such as the pay-TV and pay-per-view (PPV) services, and desire their various broadcast multimedia data to be protected and only provided to authenticated subscribers. The conditional access system (CAS) has been developed in order to solve the problems.
The CAS represents a system for allowing the subscribers who have a right to view programs to receive specific programs by applying the subscriber concept to the broadcasting, which indicates a series of processes for controlling each digital broadcasting receiver to determine whether to give a right to view a specific broadcasting program to a viewer.
Regarding general digital broadcasting, a transmitter for forming a main broadcasting network in the single or multiple frequency network is installed, a blanket area is generated in the main broadcasting network, and a repeater station is installed to service the blanket area. For example, in the DVB-T, most areas are available for directly receiving broadcasting signals, and areas available for receiving the same are acquired by using a repeater station in the areas such as subways, tunnels, and blanket areas within a building.
The main broadcasting station is generally called a key station, and it represents a broadcasting station for functioning as a main center and programming, producing, and transmitting broadcasting schedules in the broadcasting network system.
Also, a repeater station is an auxiliary station with less power, and is also called a satellite station. Conventionally, a broadcasting station has a service region, that is, a designated broadcasting region, but since boundary regions have weak radio wave arrival and blanket areas, the satellite station is installed for the boundary regions. It is installed at mountaintops for receiving radio waves from the transmitters, and it receives the waves through high-sensitivity receivers, electrically amplifies them, and broadcasts them as radio waves of different frequencies.
However, when a main broadcasting network service provider is different from a repeater service provider, the repeater service provider generates the cost of installing and maintaining a broadcasting network in the shade region, and the repeater service provider charges for the usage of the repeating network. That is, the repeater service must be a charged service for the purpose of activating the repeating network, but no appropriate treatment for the charged service has been provided up to now.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.